Tire track-partial engagement type



May 15, 1956 c. F. KOENIG TIRE TRACK-PARTIAL ENGAGEMENT TYPE 3 Sheets-Sheet 1 Filed Feb. 9, 1955 INVENTOR. CQr/ E /f 06/713 BY E 6Z5, W/yzg fjzzzw & 947W ATTORNEYJ May 15, 1956 c. F, KOENIG TIRE TRACK-PARTIAL ENGAGEMENT TYPE 3 Sheets-Sheet 2 Filed Feb. 9 1953 L 4 a I) 49 INVENTOR. Carl F K 06/13 BY ATTORN 6 May 15, 1956 c. F. KOENIG 2,745,460

TIRE TRACK-PARTIAL. ENGAGEMENT TYPE Filed Feb. 9 1953 3 Sheets-Sheet 3 INVENTOR; (ar/ E Koen/ ATTORNEYJ United States Patent .TIRE TRACK-PARTIAL EN GAGEMENT" TYPE .CarljtF. Koenig, Lyndhurst,-hio,=assignor, by mesnetassignments, to General Motors Corporation, Detroit, Mich., a corporation of Delaware ApplicationFebruary9,1953, SerialNo.j335;781

:3:.Glaims. :(Gl.15.2--.1 ,82)

:vide a, novel combination'between a large.size pneu- "maticgtire having grooves or indentationsatleast;in the "zones where the side walls 'meet' the-.trealdro'f, the tire,' toge'ther' with an endless 'track comprising, a plurality of frigid shoes havingadriving engagementwvitli-the'tire, enteringdnto the grooves or -recesses-- thereof, Whereit is flat on' the ground "under" load, *but' otherwise the track "being freeto creep along-the tire.

The preferred embodiment shown for-carrying out'the purpose' expressed-in the preceding paragraph-comprises 'a'nack' composed of-shoes Which-have a*flatmid-portion extendingaeross the major-portion "of the tread (ii-"the tire, each of these shoes having end portions extending aradially inwar'dly from the ends of the mid-portion of "theshoe,these end portions having ridges- Which'extend inwardly therefrom in position to enter into thegrooves 4or recesses i-n those por'tions -only-where *the tire 'bulges "Hater-ally outwardly under load Where n .-.contacts 'the :ground.

' IO-ther- -objects-=and:-advantages-of my invention--Wilhbe :tapparent firom':the accompanying draWingS aHddescri gtionnand the: essential "features thereof be set' forth i-inithegappen'ded claims.

.Inqthedrawings,

"aFig. 1: iseagsidelelevationah view showing-a-pneumatic zizireawithvmy Limpreved endless traekir'm positionon -the ziire, rand, the: entire :combination under i load. In ziheruppersleft-hand portion :of' this: viewithe tire. isshown in:sidezclevationswhilez'thegtrack':shoes iare shown in cenztraLasecfionalwview, aand. the supper'i'ighehandvportion :ofcthis yiewz'ihextire hasabeenncompletely: cutaway and qthe 1336143511068. are:shonm'q-imcentralasectional' View;

; Kigali isaaztransverseaseetional View ataken; along *the line 2-2 of Fig. 1;

Fig. 3 is a sectional view taken along the line 3-3 of Fig. 2 andaextendingaround 'that portionof the tire indicated on the-lines'3-3 =of'Fig. 1;

Fig..4 is a top plan view enlarged of. a portiomof .the trackjflattened against'the ground, this view being. taken fromfthe position ofthelines of Fig..ll.withzithe the omitted; while Fig. 5 is a perspective-view of asingle shoe of the track.

Ofithe,-.highway vehicles uselarge pneumatic tireseboth .-If0r. the. purpose of carrying the load. and for the purpose of'floating the load on a large supporting area, this being especially necessary where ground conditions are poor for supporting loads, such as in mud and sand.

With the increasing use of greater power for driving such vehicles, it is necessary to increase the tractive efiect of such tires in order to handle the loads involved. The present invention applies an endless track of metal shoes surrounding the entire tread of the tire and extending Patented .May 15, 19.5.

ice

slightly around-the sidewallsofthe .tire.s.o as to given protective effect. to ,the pneumatic. tire .and V at the same timeto increase the tractive eflect .when..such tires..-.are driven in order to propel the vehicle. .The. tire. illustrated herein, is an 18.00 x25 tire which: meansthat its. overall diameter is approximately .five feet. My inventionzis intended for successful. operationwith tires ofithissizeor larger and, utilizingjnternal. pressures of between..25...and 35 pounds per square inch or, less.

,The tire 10' illustrated: herein isof 1 this character. .1 It will be understood that such tires usually. have innentubes but for clarity the. inner tube has been omitted. from Fig.2.

The track 11 is composed..of.a-,plurality .ofnigidshoes 12, preferably. of steel .or iron, and having =..articula1ing .(Jr hinged connections between adjacent shoes. One .of these shoes is. morev clearly. seenin FigS.'.4-.and 5. iPreferably, .each shoe .is longer. crosswise of. the tirethan itsextentcircumferentially of the .tire. ,Each. shoehas ;a flat tread-engaging mid-portion -13 which extendsv crosswise of the tread for a major portion of the vvwidthnfthe tread as clearly.seen. at the topof Fig.,2. Ateachend of this mid-portion, wingportions 14' areprovidedwhich extendgenerally radially inwardly, fromftheends of the mid-portion and partially embrace the sidewalls ..,,of .the tire. .Preferably,.these wing portions flare ,outwardlyand upwardlyifrom .the mid-portion 13.asviewed:in.Fig. 5. 'The portions13. and ,14..are. of .metal of comparatively uniform thickness, and .of. such .a thickness to, give sufficient, strengthv tolthe. shoe, butwithouf being. very. heavy. ".This ,same thickness of metal .is bent .downward.;.at one 'side.as". indicated at,..15 .in'Fig. .lJto provide a.w all from ..whichsex endtwoshinge,lugs ,16. having through openings "16a to receive hinge pins. On the othenside of the. shoe, a walll'l extends .downwardlyfromnthe; portions; .13-.-and j14 and this wall .is .preferably..extended.on down.v beyond the mid-portionli to form agrouser. 17a extendingfrom side to side..of.'the shoe. .-From the wall I7,.the..hi n ge jlugs.18,..three of,th,em,.extend in adirection opposite the hinge lug 16. ,These. lugs. alsohave through openings '18a to receive hinge pins. Thelugs 16 and 18..are-. .s0 spaced at the lugs 16 fitsnuglyhetween the. lugs.18 -of Itheadjacentshoe when'thetrack is assembled as shown inl F ig. A. -,Hinge .pins .19..are..then,passedthroughthe lugs I6 l and 18. ;My.irnprove d ,track.;is.idesigned f0r..operation. with,a 'tirejhaving evenly ,spacedfgroovesor recesses Zilextending more or, less crosswise oi. the tire, ,at..least in .the

zones where the side walls meetthetread. .:It.will begin- ,derstood that wherever. I have referred .to these-recesses as grooves have refierred ,to them .ias. extending cr,osswise.o the. tire,..any deformation .in-.the.: tire--which ,permits it to .be locked .toJmyirnproved shoe, tshown .herein, is satisfactory, for the ,operationof my, invention.

. ILwill-be understood, looking. atFig. 2,. that the. grooves ,20 might. extendrentirely, acrossthe tread of. .the-;-tire-. but they a-re ,utilizedfor, lcckingthe .tireand the track. together only. at those zones-where ,the .side walls. meet. the

tread .ofthe tire.

For .thepurpose of locking-.the track1with the tire in .driving relationship .v/here the ,tire isrresting :fiat .upon .the. ground, Lprovide ribs on the-wings. i each. shoe, ,theseri'os being-adapted toenter into ,the, grooves .20 on yc-iume zouesiwhere the side..-Walls.meettheatread of ,the ,tire .andonly. .where the tire is flattened-on. the ground under load as shown at the bottom of Fig. 2. One of these ribs 2i is formed upstanding inwardly from each of the wings 14 in position to enter into the grooves 20 of the tire when it bulges laterally outwardly under load in engagement with the ground as indicated at the bottom of Fig. 2. it is well known that the grooves 20 molded in an evenly spaced arrangement around the tire, will lie somewhat closer together when the tire flattens where the driving action occurs.

against the ground as shown atthe bottom of Fig. 1. My track is so designed that thedistancebetween adjacent ribs 21 on the same side of the tire, as viewed 'in Fig. 4, have this reduced spacing of the grooves 20 in the tire when it is flattened on the ground under load. 'I j When the tire and track are assembled asshown in Fig.1, the track is caused toprovide s'ufiicient radially inward compression on the tire tread to cause the normal rounded contour of the tire to be flattened slightly, across the flat surface 13 of the track shoe. When the vehicle is under no load or light load, some'flatness in the tire section occurs thus all around the periphery of the tire casing. t is well known that the outerperiphery of the tread of the tire becomes 'slightly less when the Wheel assembly flattens against thefground under load as indicated in Figs. 1 and 2. Without my invention, this would cause a' loosening of the track 11 upon the the it); The fact that the tire is originally flattened all around its periphery against the flat surfaces 13 of the track shoes, creates a condition so that the tire will exert a substantially constant follow-up pressure to keep the belt tight.

in all phases of operation. Referring to Fig. 2, where the tire 110 is flattened against the ground, the tread and side walls bulge outwardly against the wings 14 of each shoe. e Some of the air in the internal chamber of the in the tire, for instance, 30 shoes and 29 eflective grooves. This is because 29 times the average spacing of the grooves around the entire tire approximately equals30 times the spacing between ribs 21 of adjacent shoes (or. 30 times the spacing between grooves 20 at the ground- I engaging portion of the tire, which is the same as the tire along the ground portionof the tire is forced around and shoes of the track is quite limitedas illustrated at the top of Fig. 2. This limited area of contact around a large portion. of the tire reduces the friction between the tire and the track. 7

I utilize the bulging of the tire side walls laterally outwardly, when under engagement with the ground, to cause interlocking of the ribs 21 with the grooves 21 The parts are so designed that the ribs 21 seatsubstantially in the bottom of the groovesj2l along the portionof the tire flattened against the ground. Since thespacing .of the ribs 21 in the track is the same asthe spacing in the grooves 29 at this flattened portionof the tire, the track and tire are positively geared together at this point Around the other portions of the track, as illustrated at the top of Fig. 2, the rounded contour of the tire holds the grooves 20 away from the ribs 21 as clearly shown in Fig. 2. Thus, the

In Fig. 3, I have shown at zone A the ribs 21 out of contact with the grooves 20. At the zone B, I have shown the ribs 21 as slightly out of registration with the grooves 20 where the track is bending to lie flat upon the ground. At the zone C, I have shown the ribs 21 firmly embedded in the grooves 20 at this portion of the tire. Since at least three sets of ribs 21 and grooves 20 are in positive engagement on the ground-engaging portion of the assembly at all times, a rib 21 in the zone B is forced into its appropriate groove 20 justbefore the track and tire flatten on the ground. At zone D, I have shown the ribs 2 1 slightly out of registration with their associated grooves 26 at that point where the track is leaving the ground. In the tire and track illustrated, there is a pair of ribs 21 on each shoe .12, and there is one more shoe than there are cooperating grooves 20 spacing of ribs 21 measured between adjacent shoes).

The ribs 21 are substantially in line with the wall 17 so that this wall provides a direct connection between the tire engaging ribs 21 and the ground-engaging grousers 17a.

.What I claim is:

1. In combination, a pneumatic tire having side walls and a tread, said tire having evenly spaced grooves extend-. ing cross-wise of said tire at least in the zones where said side walls meet said tread, said tire being of a construction and having a normal working pressure such that the portion of said tire engaging the ground flattens under load so that said evenly spaced grooves temporarily lie at a reduced even spacing along said ground-flattened portion of said tire, an endless track completely surrounding and tightly engaging the circumference of said tire, said track comprising a plurality of rigid shoes and articulating connections between adjacent shoes, each of said shoes having a flat mid-portion engaging the tread of said wire, each of said shoes having end portions extending inwardly from the ends of said mid-portion and lying opposite said zones, said end portions having ridges extending inwardly therefrom and spaced at said reduced even spacing, and said ridges having such an inward extent that they have driving engagement with said grooves only at said ground-flattened portion of said tire. I

2. The combination of claim 1 wherein said ridges are inclined laterally away from said flat mid-portion of said shoe, whereby the flatter the tire, the greater is the extent of the ridges engaged into said grooves. 3. A shoe for use in an endless tire track to be applied 2 to a pneumatic tire having evenly spaced grooves extende ing circumferentially of said tire, said shoe having a midportion generally flat on its tire-engageable surface, said shoe-having end portions at opposite ends of said midportion extending radially inwardly of the tire from said mid-portion on the tire-engageable side thereof, a wall along one side of said shoe, said wall extending downwardly beyond the mid-portion to form a ground engaging grouser, at least one ridge on each of said end portions only, said ridges extending laterally outwardly away from said mid-portion of said shoe and having a length substantially equal to said end'portions, saidridges having curved tire engaging surfaces, and being substantially in alignment with said wall and the ground engaging grouser of said shoe, said ridges being spaced apart laterally by a distance greater than the tread cross section of a fully inflated pneumatic tire with which it is intended to be used, whereby said ridges enter into the grooves of the tire only when said tire bulges laterally outwardly under load in the zone of ground engagement.

References Cited the flle of this patent UNITED STATES PATENTS 1,307,036 Bretscher June 17, 1919 1,413,167 Knisely April 18, 1922 2,046,299 Armington June 30, 1936 I FOREIGN PATENTS 269,378 Switzerland Oct. v16, 195

858,389 France Nov.: 23, 19 40 

